Method for the combustion of liquid fuels



E. BECKER METHOD FOR THE COMBUSTION OF LIQUID FUELS Sept. 15. 1925 Filed May 5. 1923 Patented Sept. 15, 1925.

' UNITED STATES ERICH BECKER, or BAD soonnn, GERMANY.

METHOD FOR THE COMBUSTION OF LI Q' UID FUELS.

Application filed May 5,

To all whom it may concern.

Be it known that I, Enron Bnoxnn, a citizenof the German Reich, residing at Bad Sooden, Germany, have invented certain new and useful lmprovements in Methods for the Combustion of Liquid Fuels, of which the following is a specification.

This invention relates to a method for the combustion of liquid fuels for heating purposes and it has for its object to ensure in utilizing the well known advantages of the combustion method with the use of the so-called gasifying burners in which the gasification or vaporization of the oil is produced prior to the combustion, a thorough mixing of the air with the oil gas with the least possible excess of air. With this object in View a downward direction is given to the flame produced from oil gas and preliminarily heated primary air, and secondary air, heated to a higher degree, is added to the flame.

According to the invention the improved method is as follows The gases of the liquid fuel supplied to a circular gasifying gutter, said gases being produced with the aid of the heat rising from thecombustion chamber, are forced to flow into the combustion chamber in downward direction owing to the special shape of said gasifying gutter and its cover, primary air preliminarily heated to a moderate degree by coming in contact with hot parts of the burner are admitted from above so that this current of primary air draws the gases on in downward direction and admi-xes with said gases to form a flame. By the downward direction of the flame a thorough. admixing of gas and air is ensured as the specifically lighter gases, in opposition to their natural tendency to ascend in the specifically heavier air, are caught by this air and conducted downward into the combustion chamber under formation of eddies whereby a slightly checked waving flame is produced. ,The formation of a pointed flame is avoided inthis manner.

To the lower end of the downwardly. directed waving flame thus produced a convenient quantity :of secondary air, which has been preliminarily heated to a higher degree than the primary air is then added with the aid of'a central metal tube arranged at the centre of the burner so that it projects downward into the centre of the combustion chamber, th W 1 9f th s cent al tube oil burner.

1923. Serial No. 637,022.

being thus strongly heated by the heat of the flame. This tube has preferably holes in its lower part through which the secondary air flows out in lateral direction so that it strikes perpendicularly upon the inner surface of the flame.

. By this 'methoda flame of such high heating power is produced as could not be obtained hitherto so that the method of combustion may be preferably used in connection with metallurgiccarbonicand cement- .motive furnace. I I

Referrlng to F 1g. 1 the combustion takes place in a chamber3 which is formed by a cast iron cylinder 1 lined with refractory material 2. The burner has an outer casing 4t of sheet iron. v

The liquid fuel is supplied by the feeding pipe 6 with regulating device 5 to an annular gasifying chamber 7 In this chamber the liquid fuel, for instance oil, 1s gasifiedby the heat radiating from the flame which is formed in the combustion chamber 3 and with the aid of an air current flowing into the space 8 between the casing 4 and the cylinder 1 through the in let opening 15. The air current is heated in flowing along the outer wall of the cast iron cylinder 1. i The air which is thus preliminarily heated flows around the gasifying chamber 7 through the annular slot 9 and over the vaulted cover 10 of the gasifying chamber, The gasifying gutter 7 is mounted by means of distance holders 11 upon the refractory wall 2 of the cylindrical The ring-shaped air grate 12 dof consists of concentric rings a, b, c an a conical centre piece or it can consist of separate removable rings. In the latter case the advantage is obtained that, if one of the rings should be damaged, it can be removed and replaced by a new ring. The ring-shaped grate 12 is'mounted in the apparatus preferably at such a height that it is sufiioiently distant from the combustion chamber 3 and therefore possesses'considerable resisting capacity, the ring-shaped grate is composed of several parts the rings are preferably mounted the one upon the other by means of radial extensions 6, the outer ring held upon the inner surface of the vaulted cover 10 of the gasifier by means of longer extensions f; The ring shaped-ai-r grate could also be suspended upon the inner lower edge of the vaulted cover of the gasifier, in which case this lower edge ought to be of a special convenient shape. It is essential that the cross section of the several rings or of the ring system adapts itself to the surface of the va'ulte'cl cover of the gasifier' as in this manner a conicjalsh'ape will be given to theair' current which traverses the grate. The secondary air which flows through slot 9' will adopt a' similar conical shape owing to the profile of the lower part of the gasi'fier and to] the profile of the upper end of the wall 20f refractory material. If the apparatus has to he of large dimensionsin order to generate a greater amount of heat the gasifier is preferably subdivided a-nd the different parts of the same are connected with onennother by elastic refractory p'aclzings in such a manner that no tension is produced by the expansion caused by the heat. The gasifying' gutter" 7 can be divided according" to its size into two, three or more parts and it could have more or less deep incisions at the inn r edge wl'i'ich is most exposed to the expansion by heat. y

The primary air which is preliminarily heated in the space 8 of the casing" flows partly through the grate 12; into the combustion chamber 3 amt partly through slitshape'd openings g arranged at the lower edge of the cover IO oftheiga'si'fier; so that the oil-gas geiierated'i' i the ga'sifier is" thoroughly admixed with the preliminarily heated primary air and the conveying of the oil gases from the gasifi'er is simultaneously ensured. The airflowing throi'igli 9 forms a heat insulating,- continuously' inoving layer so that the ghs'ifihati'on'ih 7 does not take place under vthe direct action of the heat radiating from 3 and Q, whereby it hecomes possible to avoid the coking temperature of the liquid fuel and consequently formationof cokelike' deposits in the gasiher. The combustible. mixture of oil gas and air is ignited under the grate 121, The secondary air which is reqiiired fo'r' ensuringl thecomplete combustion of the oil is supplied through the; slot 9" mentioned above. Theair which has been already preliminarily heated flows; in the slot along the refractory" lining 2fof' the combustion chamber which is heated to a very high'degree; so that the secondary air arrives" in the combustion chamber heated at a temperature which is much superior to" the temperature which exists at' 8,: I2 and 9.-

Besides the slot'9 washer-sierra can be arranged in which-the air flowing in from space 8 is heated also. As this branch current is in contact with the upper and lower h'ot walls of the slot 13 it does not loose any heat by radiation to the gasifier, this air is further preliminarily heated to an increased temperature 4 in comparison with the air flowing in through 9. If desired, another air current which is preliminarily heated to a still higher degree of temperature could 7 be" conducted into the combustion chamber by means o'fl an extension of the" air' inlet slots or by displacement of these sl'ots. In this case the gradual preliminary heating of the air for combustion is eliected in such a manner that the prini a'ry air' flows along the hot outer surface of cylinder 1 and the secondary air over the upper edge of the hot lining 2,- the third air cur'renttraversing the lining 2 which is heated up to iIi- 8 candescence; The gases from combustion which are thus heated to very high ten'iperature" flow out through a fine 145 from the 'comhu'stion chamber to the objectto be heated. i 9

As soon as a heating de'yice of the" above described type exceeds a determined size it is advisable to use not only one annular gasifier' and only one" cylindrical refractory wall but to subdivide the heating chamber in such a manner that two or Ii'IOIe concentric' g'asi'fie'rs and as many concentric refractory cylinders are provided in the casing. Between;every two gasifie'rs an air grate is arranged the bars of which are, in this case, parallel with the axis offthei gasifier. Under the ga'si'ii'er the refractory walls are arranged between which thefl'anre' is formed.

n In this manner it i's possible to bring the flame to uniform development even if the burner is of large size and to' obtain the same favor'al'ale adniiXin'g with the combustion ail-"as in the burn'ers of smaller size.

The supply of the heating oil is prefera'bly regul'ated hy the valve in such a; manno ner that only so muchjoil flows c'ontinuousl in at 7 as is gasifie'd byth'e radiating heat.

Fig. 2" represents a dey'ice usedl as locomotive furnace. It consists essentially of a" body 2 oi refraictory material, for instance of fire brick, extending along the en' tire length of the" firebox 1 and supported inthe same in a con'veni'ent'manner from all sides, and for a gasifyin gutterfi which is arranged in the hire brickiwal'l andex 12o tends also in longitudinal direction. The g'asifie'r which, in this form of"construction,

has an elongated shapecan be subdivided also in this case into seyera'l parts ifburrrers of larger size are" to be used. This is profitabl with respect to the better adaptation to the expansion under heat and further "for the reason that certain partsof 'theg'asii hear should be damaged they can easily be replaced:

Instead of a single gasifying chamber two or more straight and parallel chambers could be provided.

The gasifying chamber consists, in the form of construction shown by way of example in Fig. 2, of a saddle-shaped iron gutter which is covered by a hood. This gasifier is arranged at the height of the fire door 4 so that it can be easily removed I from the burner.

The gasifier is preferably suspended upon a guide rail 5 extending in the direction of the axis of the firebox. The gasifier can however be fixed also upon the cast iron envelope of the inner fire brick wall 2*. The removal of the gasifier is necessary only for the purpose of cleaning. In this case the gasifier can be cleaned without any loss of time simply by removing the gasifying gutter and inserting another gutter which has to be kept in store. The liquid fuel to be burned is preferably stored in a reservoir gutter stands almost horizontal and the oil is level in the same.

In order to facilitate the necessary exchanging of the fire tubes of the boiler the burner body is preferably arranged so that it extends not over the entire length of the furnace and that a convenient interval is left between the gasifier and the front wall of the boiler. The supply of heating oil is preferably regulated by a regulating device in such a manner that only so much liquid fuel is supplied as is gasified. The gasification is obtained by means of heat radiating from the combustion with the aid of the air for combustion preliminarily heated upon the walls of the fire brick body in a very uniform manner which prevents excessive heat or coking of the oil. The gasifying gutter is surrounded on all sides by currents of preliminarily heated air and it is thus not exposed at any point to the direct heat from combustion, so that the cleaning and exchange of the gutter is required only at very long intervals.

The combustion air rises from the free lower surface of the locomotive through the central channel 11 and separates into twojets flowing into the furnace. The primary air which effects the ignition of the gas produced in the gasifier flows into the space between he ower su face of the fire br c dome 2 and the upper surface 10 of the vaulted cover 3 of the gasifier and is sucked downward from this space by the natural bottom draught of the, locomotive partly through the grate 9 and for the smaller part through the slits 8 provided in thegasifier cover. The preliminary heated primary air flowing through these slits efiects the mixing of the oil gas flowing out from the gasifier gutter and assists at the same time the guiding of the gases in downward direction. Under the grate a downwardly directed ignition flame. is produced of oil gas and preliminarily heated primary air, to which more air, which is more strongly heated, is added. This secondary air hasbeenvhighly heated in rising in the flue 11 formed between the two fire walls 2 and it effects the thorough combustion of anything combustible in the ignition flame. More auxiliary air, heated to a still higher temperature, can eventually be supplied through the adjustable slits 12 to. theflame which burns in downward direction in 13' whereby the amount of heat generated by the device can be further in creased for a more intense working. These slits 12 can be completely closed if desired.

The hot heating gases produced in 13 change their direction of flow at the-lower edgel: of the firebrick dome and'rise along the side walls of the firebox in evaporating the boiler water which surrounds the fire box. These gases flow further along the entire surface of the firebrick dome and heat the same whereupon they flow off at 15 over i the end of the firebrick dome into the space between the burner and the end wall of the boiler and from there into the fire tubes of the locomotive-boiler. In these fire tubes the heating gases give up their heat to the water of the surrounding boiler which they evaporate, and they serve further for heating the steam superheater. The heating gases escape from the fire-tubes, where they have been deprived of almost all their heat through the chimney into the atmosphere.

The device which has been just described "in its application to the oil firing of a locomotive can be used in modified form also with stationary boilers, specially marineboilers. The length and cross section of the device must however be adapted to the size of the boiler furnace. With stationary boilers it is not necessary to arrange the gasifier at an inclined position. With stationary boilers it is further not absolutely necessary to mount the device in the furnace. With locomotives it is very advantageous to mount the gasifier in the firebox as there is little space available in the engineers cab. lVith marine-boilers the ap paratus could however be mounted for instance in front of the furnace, outside the boiler. The mounting of the apparatus in the boiler presents the advantage that the tion of steam by radiation.

heat produced at the combustion is entirely utilized for heating the boiler whilst, if the apparatusis mounted in front of the boiler, part of the heat will be lost for the produc- The mounting in front of the boiler has however, on the other hand, the advantage that the oilbu'rner can be rapidly and easily exchanged against another furnace, for instance coalfurnace. The mounting of the oil-burner in'existing furnaces, for instance in the fire box of locomotives which have been hitherto heated with coal, makes, not much difliculties and does not cause considerable ex penses.

Any kind of liquid fuel, for instance oils which have a high boiling point or residues from the mineral oil industry which are rich in constituents possessing a high boil ing point, and further fuel which is solid at normal temperature, can be burned, this latter kind of fuel having however to be liquefied before it'is admitted into the 'gasifying chamber. 1

I claim:

1; A method for the combustion of liquid fuels after the gasiflcation or vaporization of said fuels bythe action of the heat from the zone of combustion consisting in condfucting the gases in a downward direction in the zone of combustion, in adn'iiXin-g the gases with primary air preliminarily heated to a moderate degree, said primary air being admitted from above at the center of the flow ofgases to produce a downwardly directed flame and also around the flow to envelop the same, and in adding to this flame secondary air which by the heat from the flame has been previously heated to a higher degree than the said primary air.

2. A method for the combustion of liquid fuels after gasiflcation and vaporization of said fuels by the action of the heat from the zone of combustion consisting in conducting the gases in a downward direction in the zone of combustion and passing the total quantities of fresh air upwardly e2:- teriorly of the zone of combustion and heating the fresh air while ascending dividing the fresh air into primary air and secondary air, and mixing the gases with the primary air, said primary air being conducted down-- wardly at the center of the flow of gases to produce a downwardly directed flame, highly heating the secondary air and conducting the same into the zone of combustion and mixing the said secondary air with the gases and primary air.

In testimony whereof, I aflix my signature.

ERICI-I BECKER. 

